Lubricating composition



United States Patent Office 3,095,374 Patented June 25, 1963 3,095,374 LUBRICATING COMPOSITIN Richard E. Baus, Philadelphia, and Earl E. Fisher, Glcnolden, Pa., asslgnors to Gulf Gil Corporation, Pittsburgh Pa., a co oration of Pennsylvania No Drawing. Fixed pms,19s7,ser.N0.sss,ess 4Claims. (Cl. 252--18) This invention relates to lubricating compositions and their prepa-ration and particularly to lubricating con-iposid tions having wear and corrosion reducing characteristics which suit them for use in the lubrication o f Vinternati combustion engines. f ,L v

ADne'to theiconditions encountered in the lubrication of the cylinders of internalkcombustion engines,` particulariy the formation of acids'. 'the Wear' of piston rings, cylinders and cylinder walls 'is drequently excessive'. Pe-

. troleurn lubricating oils in general need improvement to combat excessive `Wear which ins conditionsl While the problem ot' combattingengine' wear is important-in the lubricaiton of alltypes of intcrnalicornoccurs under engine operat- .bustion engines, the problem is particularly serious .in

the lubrication of low-speed marine diesel engines which operate on fuels having high .sulfur content. Itis known, for example, thatresidusl fueloilsjcanibe'used to power iow-speed marine diesel engines in iieu of the more costly rosion and erosion of cylindr'ovalls and pistons.V 'The suicient to maintain the magnesium Auniformly suspended'in the lubricating oil.

lighter diesel fuels. Howevrfi H Slswcll known, heavier manner, it is available as a protective coatingcn the metal `surfaces of the cylinder to effectively neutralize the acidic combustion products thus preventing metal i surfaces from attack. The magnesium carbonate is employed as a tnely divided powder in order to assist in obtaining stable suspensions. In general, the size of the magnesium carbonate particles should bc on the onder of -l amounts of magnesium canbonate asfhigh as 10% by petroleum fractions generally contain higher concentrations of sulfur than do the lighter fractions. .Experience has shown that diesel engines operating on these `heavy high sulfur :fuels have serious :nairrteoance problems in the form of excessive cylinder weer. It is believed that the high concentrationy oiu sulfur the fuel is rei sponsible in great part for the excessive 'wear since fuelV containing large quantities of sull-ur canlceuse both corcon'osive wear occurring 'within engines operating on this typo of, fuel has been attributed specifically to the 'acidic vapors auch as 'sulur dioxide and sulfur trioxide formed on combustion of the sulfur containing fuels. Infthe presence ot' water which 4is formed dining combustion and which may result from moist air entering the engine through the air intake, these sulfur-ous vapors attack the exposed metal parts. i It has now been found that improved liquid lubricating compositions which exhibit excellent antiwear properties are provided by n'uniform'blend of a major amonntof a lubricating oil and a minor amount suilicient to confer improved 'wear properties; to the'composition of magnesium carbonate and a small amount of a magnesium carbonnte The lubricating oil whidr constitutes themajoringredient of the new composition is selected wide variety of htbricating oils sodi as naphthenic base, paretnic base and mred base mineral oils. In general, 'any mineral oil of tnbricating viscosity or synthetic lubricant lng oils such s polymerized olelins, organic esters such as di-Z-ethylhexyl sebscate and azelate andthe like.' are used as the base oil to form a lubricating composition in accordance 'with this invention. For thejlubrication of low speed marine dieselengines a-mineral lubricating il having a viscosity in' ythe range 1000 to 3000 S'aybolt seconds'- at' 100 F. is generally employed. The magnesium cnr'bdnate'is dispersed and maintain suspended uniformly throughout tlie lubricatingil base to impart to the compsitionthe desired wear and corrosion reducing characteristics. By having the ms. 'nesium carbonate present in the lubricating oil .in .this

and is preferred.

weigtlxtor higher can advantageously be employed. For

many applications including the cylinder lubrication of Y low speed marine diesel engines burning high sulur fuels, 3% by weight 4ol? magnesium carbonate is, satisfactory 'Ihemagnesium stearato additive ofthel invention is eitherta neutral magnesium stearato, that is, magnesium distearate, or a basic magnesium stearato, that is, magnesium hydroxy stearate wherein, only .one hydroxyl group has been neutralized 'with the stearic acid. Both of these materials as well as mixtures thereof are substantially equally effective Ifor the purposes of this invcnticn. i Y Although both the magnesium 'stearato and magnesium carbonate. ooact in the compositions of the invention to reduce corrosion and wea-r within the cylinder, the magnesium stearato additive iunctions primarily as n dispersing -andsuspending argent to maintain' the magnesium carbontae effectively endunifomly dispersed throughout the lubricating oilvbase. While stable lubricating Vcompositions are' obtained when the magnesium stearato is employed in 'amounts' as .small as 0.25 9b -by'weight 'of the composition, the maximum amount of magnesium stearato should'uot exceed about 6% to avoid gelation of the composition Vto form'agrese. Wherethe magnesium stearato is employed in amounts of from about 0.25% to vabout 6% by'weight, the magnesium can bonate is maintained'in' proper and 'permanent distribue tionthroughout the lubricating oil-base and does not tend to separate readily'ther'efrom, 'the entire composition nevertheless being a liquid as desired and not a grease.

In preferred composition, 1 percent by Weight of magnesium stearato' is employed.

The improved lubricating compositions' ofthe invention are prepared by the magnesium carbonate andthemagnesium stearato, in amounts suiclent to give a desired concentration in the iinal composition, with .a portion, as for example one haii, of the base lubricating oil. mixture is then heated with continuous agitationto a temperature of from 250 to 350 F. or higher, to dissolve the magnesium stearato. 'When the magnesium stearato has been completely dissolved, 'the' remaining por; tion of the base. lubricating o il issdded while maintaining a temperature ofljtlf to 350" P. The mixture is then ooled with -orrtinurnnr agitation -to a tempramre of about F. or lower. Using this procedure gel formation-is eectively preventedand a' A'uniformly blended, stable, liquid lubricating 'oil composition -is obtained. 'I-'he following examples further illustrate the invention,

i which is not to be construed as limited thereby. Inthese examples, the base oil employed was a blended lubricating oil obtained from mixtures of dewaxed, solvent refined lubricating oil stocks, having the following inspection.

Gravity, API 25.1 Viscosity, SUV, sec.:

100" F 1050 210 F 80.1 Flash, O C., F 475 Fire, O.C., F 530 EXAMPLE I Make-up, percent by Weight:

lOil base 96.0 Magnesium carbonate 3.0 Magnesium hydroxy stearate 1 Inspection:

Gravity: API 22.2 Viscosity, SUV, sec.:

100 F 1987 210 F 236 lFlash, O.C., F 495 Fire, O.C., F 545 Neutralization value, ASTM D 664-54 (potentiometric) Total base number 2.20

EXAMPLE II Utilizing the same procedure as in Example I, a composition is prepared having the following make-up and inspection.

Make-up, percent by weight:

Oil base 95.0 Magnesium carbonate 3.0 Magnesium hydroxy stearate 2.0 Inspection:

Gravity, API 21.8 Viscosity, SUV, sec.:

100 F 3160 210 F 1325 Flash, O.C., F 495 Fire, O.C., F 545 Neutralization value, ASTM D 654-54 (Potentiometric): Total base number 4.70

EXAMPLE III Utilizing the same procedure -as in Example I, a composition is prepared having the following make-up.

Make-up, percent by weight:

Oil base 96 Magnesium carbonate 3 Magnesium stearato 1 EXAMPLE IV Utilizing the same procedure as in Example I, a composition is prepared having the following make-np.

Make-up, percent by weight:

Oil base 93 Magnesium carbonate 3 Magnesium stearate 4 EXAMPLE V Additional uniformly blended stable liquid antifvvear lubricating compositions -are obtained using the same lubricating oil base and in the one instance 0.1% by weight of magnesium carbonate and 0.25% by weight of magnesium stearate, and in the other instance 10% by weight of magnesium carbonate and 6% by weight of magnesium stearate.

The stability of the lubricating compositions containing the magnesium additives is determined by subjecting a measured volume of the composition to varying temperatures over a 48 hour period. Inspection of the sample is made at various temperatures and the percent separation by volume determined. Using this procedure the following results were obtained:

Oil ot Oil of Oil nl Oil ot Ex. I Ex. Il' Ex. [Il El'. lV

Stability test, separation, percent:

24 hours:

Oil Nil Nil Nli Nil Sediment Nil Nil Nil Nil 2 F.:

Oil Nil Nil Nil Nil Sediment- Nil Nil Nil Nil Nil N il Nil Nil Nil Nil Nil Nil il Nil Nil Nil Nil F Nil Nil Nil Nil i 11 Nil Nil Nil Nil Sediment Nil. Nll Nil Nil F.:

ll 0- 5 N il 1 Trng@ Sediment Nil Nil Nll Nil 48 hours:

Oli Nil Nil Nil Nil Sediment Nil Nll Nil Nil 32 F.:

Oil N11 Nil Nil Nil Sediment, N11 Nll Nil Nil Ambient temperature:

011 Nil Nil Nil Nil N il Nil Nil Nil N il Nil Nil Trace Nil Nil Nil Nil Nil Trace Nil Nil Nil Nil Nil 1 1B Nil 1 Trace 3 Nll N ll Nil 1 As seen from the above data, there is very little tendency for the magnesium additives to separate yfrom the oil base even at temperatures not normally encountered in storage. Accordingly, the wear reducing and corrosion inhibiting properties imparted to the lubricating compositions of the invention by the magnesium compounds are effectively maintained while permitting the composition to be stored for extended periods.

To illustrate the wear reducing properties of the improved lubricating compositions of this invention a four ball wear test is conducted as follows: Three steel balls are securely fastened so that rotation is impossible. A fourth steel ball lin a rotating spindle is placed so that :it is entirely supported by the other three :balls forming .s pyramid. The three immobile steel balls and the ro- 'iating single steel Iball are forced into Contact with each other in response to a vertically applied load. Suicient test lubricant is poured into a test cup to cover the three lower Iballs at -a predetermined depth. The spindle is revolved at 1800 r.p.m. while electrical heating units heat the oil to a temperature of 266 F. At the conclusion of -the test, wear is measured Eby examination of the scars on the clean surfaces of the three stationary balls; the two maximum right angle diameters of each wear scar being measured to the closest 0.01 mm. and averaged. The antiwear properties are rated by the difference in -the scar diameters. The actual pressure exerted on each point of contact is calculated as a. function of the lever load and the scar diameter.

Utilizing the test described above, a comparison of the antiwear properties of the lubricating oil compositions containing the magnesium additives with the base oil is shown in Table 1I.

Table Il As seen from the above results, the lubricating compositions of the invention reducewear from 33% to 50% and more as compared with the base oil containing no additives.

The ability of the lubricating compositions of this invention to eiectively neutralize the acidic products formed upon combustion suits these compositions particularly -ior the lubrication of large low speed marine diesel engines which operate on high sulfur content fuels, such as residual oils and distillates which contain free or combined sulfur in amounts anywhere from 0.1% to 6% and more by weight. 'I'he lubricating compositions of this invention are suited for this type of lubrication also 'because of the nature .and quantity of the ash produced when the lubricants are burned. As is known, separate cylinder lubrication is employed in large marino diesel engines and the lubricant is subjected to combastion within the cylinder. The magnesium additives of this invention produce upon combustion an ash of a light and iluiy nature which is easily blown from the cylinder of the engine without the formation of harmful deposits therein.

It is to be noted that while the'lubricating oi'l com positions ofthe invention are particularly suited `for the lubrication of marine diesel fengines which operate on high sulfur content fuel, the utility of thev new compositions is not limited thereto. As seen from the results of the wear test reported in Table II, the new lubricants possess excellent wear reducing characteristics independend of Itheir acid neutralizing properties. Thus, the new compositions may be advantageously utilized in the lubrication of all types of internal combustion engines.

In addition to the `additives disclosedrheren, there may be present in the lubricating compositions of'this invention other conventional additives such as pour point depressants, Vanti-rust agents, oih'ness impl-overs, extreme pressure agents, viscosity index improvers and the like.

characteristics which particularly suit them for use in the lubrication of marine diesel engines which operate on high sulfur contents fuels. A further advantage of the lubricating compositions of the invention is that the compositions possess ra high degree ofV stability which permit them to be stored for extended periods of time without having their effectiveness to reduce wear and corrosion in cylinders lost or materially diminished.

The expression consisting essentially of as used in the claims means that the lubricating composition is made up of the components recited and these components are the characterizing ones. But the expression does not exclude the presence of minor amounts of ma.` teria-ls which do not materially aiect the Ibasic and novel characteristics of the composition:

Resort may he had to fthe various modifications and variations which fall within the spirit of the invention and the scope of the appended claims.

We claim:

1. A stable liquid lubricating composition consist. ing essentially of a uniform blend of la mineral 'lubricating oil containing from about 0.1% to 10% by weight magnesium carbonate and from 0.25% to 6% lby weight of a magnesium steer-ate.

' 2. A stable liquid lubricating composition consisting essentially of a uniform lblend of a mineral lubricating oil containing about 3% by weight magnesium carbonate and about i1% by Weight of a magnesium stearate.

The present invention provides liquid lubricating 'comr 3. A process for preparing a uniformly blended stable liquid lubricating composition which comprises adding to a portion of a lubricating oil, magnesium carbonate and a magnesium stearato, the magnesium carbonate being addedin an amount suilicient to constitute from .1% to 10% by weight of the final composition, the magnesium stearato `being added in an amount sufficient to constitute from .2.5% to 6% by weight of the final composition, heating the mixture with continuous agitation to dissolve the said magnesium stearato, adding additional lubricating oil in an amount suticient to form a nnal composition vot desired concentration, then cooling the sai-d mixture with continuous agitation to obtain a uniformly iblended liquid anti-wear lubricating 'composition.

4. The process of claim 3 wherein the said mixture is heated to ,-a temperature of albout'250" to 350 F.

References Cited in the tile of this patent UNITED STATES PATENTS 2,079,8614 Sullivan et al. May 4, 1937 2,417,431 McLennan Mar. 18, 1947 2,485,861 Campbell et al. Oct. 25, 1949 2,671,758 Vinograd et al Mar. 9, 1954 2,676,925 Lindstrom et al. Apr. 27, 1954 2.,781,314 Wassen Feb. l2., 1957 2,832,677 Morway et al. Apr. 29, 1958 FOREIGN PATENTS 200,149 Australia Nov. 4, 1955 716,648 Great Britain Oct 13 1954 

1. A STABLE LIQUID LUBRICATING COMPOSITION CONSISTING ESSENTIALLY OF A UNIFORM BLEND OF A MINERAL LUBRICATING OIL CONTAINING FROM ABOUT 0.1% TO 10% BY WEIGHT MAGNESIUM CARBONATE AND FROM 0.25% TO 6% BY WEIGHT OF A MAGNESIUM STEARATE. 